Did you ever play that children's party game where you have to remember objects on a tray? Well that's Kim's Game, and Dominic recommends it as an exercise to improve your long-term memory.
View a selection of objects (if you don't want to try it with a tray, you could simply use things on your desk) for a limited time, then cover them or turn away so you can't see them.
Try to remember as many as you can - write them down.
"One technique is to imagine the objects along a journey around your garden or down your street," advises Dominic. "Picture each item at various stops along the way."
The more items you use and the less time you have to take them in, the harder it'll be!
"To retain them for long-term recall, review the group of objects a minimum of five times," says Dominic.